The choice or adoption of an ideology is a complex process driven by individual psychological needs and a subjectively rational evaluation of the available options (ideologies and their narratives). This chapter presents models that describe the choice of an ideology as a subjectively rational process in which people search for ideological narratives that best serve their needs, e.g., for security, order, belonging, identity, autonomy, self-efficacy, consumer goods, and many more. This choice is initially presented in a static model of optimal choice from a menu. The second model, the dynamic model of Bayesian Learning about ideologies, illustrates how individuals with incomplete information about ideologies deal with this lack of information, gather information, and adjust their ideological beliefs over time. Once again, the costs of gathering information play an important role. The chosen ideology or ideology mix is thus the result of an individual subjective optimization process that takes into account psychological needs, material preferences, and the costs of acquiring information about the various available ideological options. The analysis also considers individual ideologies as examples. It describes how, for example, narratives of imperialism or consumerism appeal to specific psychological needs of individuals and thus individuals can become followers of such ideologies.